Evading Growth Supressors

Question 1

Quick summary of evading growth suppressors:

Answer 1

the cell is able to avoid factors that would normally control and contain cell growth and instead continue to proliferate
Eg: Retinoblastoma and P53

Question 2

Name 3 tumour suppressor Genes

Answer 2

Cyclin/ cyclin dependent kinases and cyclin dependent kinase inhibitors
Retinoblastoma protein
P53

Question 3

What do cyclins do?

Answer 3

Different cyclins in different cell cycle stages
Cyclins combined with Diff. CDK’s
Each CDK complex phosphorylates a different target protein
Pretty much: tells cell to move onto next stage

Question 4

What is Retinoblastoma?

Answer 4

Tumour suppressor gene that acts as a brake to keep cell in G1
Inhibits genes needed for S phase
Phosphorylation of retinoblastoma causes brake release

Question 5

How does mutation of retinoblastoma cause cancer?

Answer 5

Retinoblastoma inactivated by active G1-CDK complex
Phosphorylated retinoblastoma releases E2F Transcription factor
E2F transcribes genes that are required for S-phase.
Cell enters S phase

Question 6

Retinoblastoma cancer

Answer 6

Cancer of eye
retinoblastoma gene inactivated in cancer- therefore cell can progress through the stages uncontrollably

Question 7

What viral proteins can bind and deactivate retinoblastoma

Answer 7

HPV protein E7

Question 8

Sporadic cancer

Answer 8

No known cause

Question 9

Familial Cancer

Answer 9

Combo. of genetic and environmental factors- relatives may show same type of cancer

Question 10

Hereditary cancer

Answer 10

Altered gene passed down. More likely to have relatives with same/related types of cancers.
May present at earlier age.

Question 11

What is P53?

Answer 11

Guardian of genome >:)
Mutations- proliferation, dysregulated cell growth

Question 12

How does P53 work?

Answer 12

P53 interacts with CDK inhibitor P21, therefore any damage can be repaired or can cause apoptosis as cell cannot progress into next stage.

Question 13

Explain the difference between P53 on damaged DNA and no damage

Answer 13

No DNA damage: P53 binds to MDM2 and is broken down by a proteasome

With DNA damage: P53 is phosphorylated and then causes P21 gene transcription. Therefore, cyclin/ CDK complex inactivated. Therefore, DNA repair from cell cycle arrest. IF MUTATED, CELL CYCLE WONT STOP

Question 14

Tumour suppressor genes example and short explanation

Answer 14

Genes that are knocked out or removed for cancer
Retinoblastoma, P53

Question 15

Oncogenes example and short explanation

Answer 15

Genes are stuck on for cancer to occur
Ras, Raf